Fixture for machine tools



April 15, 1952 E. E. POWELL 2,592,821

FIXTURE FOR MACHINE TooLs Filed Aug. 11, 1945 s' sheets-sheet 1 iw@ wwwwww.

April 15, 1952 E. E. POWELL FIXTURE FOR MACHINE TOOLS 5 Sheets-Sheet 2Filed Aug. 1l, 1945 IVENTOR 7a/ward@ foo wel? www m ATTORN EYS April 15,1952 E. E. POWELL 2,592,4821 I FIXTURE FOR MACHINE TooLs l Filed Aug.l1, 1945 INVENTOR ATTORNEYS tionv on vthe work piece.

Patented Apr. l5, 1952 FIXTURE FOR MACHINE TQOLS Edward E.'Powell,ConimicutfRaI. A

Applicationugust 11, 1945, Serial-No. 610,268

v l This.' invention relates to a work holdingfixture which may be usedin connection with a machine tool` and. is particularly adapted toeffect an indexing and feeding movement of a Work piece relative to acutting tool.

A work piece which must be indexed 4in its machining operation usuallyrequires that an elaborate expensive machine be usedfor opera- Somefixtures have beeni attempted which .may be attached to machinef tools,but the indexing depends upon the reciprocating movement of the Workpiece toward and from the tool. A device which operaltes in this mannerhas definite limitations vas tothe indexing which may be eiected, and itis dependent .upon movements which are undesirable. Y

One of the objects of this -inventionis to provide a work holding xturewhich will be a complete unit and which may be driven from any suitabledriving mechanism.

Another objectv of this invention is to provide a unit which will bevwholly automatic in its operation.

YAnother object of vthis invention is to provideia unit in which theindexing of the work will take place independent of the movement of thework toward and from the cutter or tool which operates on the Work. l

Another object of this invention is to provide a unitwhich will becomplete within itself and which will not bedependent upon the movementof any part of the machine upon Awhich it is mounted.

Another object of this invention is to provide lan indexing unit whichmay .have a greater varifety of movements possible thanwere theindexingmechanisms built into the machine such as provided in a previously knownmanner.

Another object of this invention is to provide a fixture which may bemounted upon any machine tool table.

Another object of this invention is to provide a device which will notbe dependent upon the stroke of thecarrier for the work in-its movementtoward and from the operating tool, and thusvone which will not'sacrifice any of the stroke of the carrier for doing some other part ofthe work in the mechanism.

Another object of the invention is to provide a locking mechanism whichwill be strong and -yet productive of a large vnumber or positions inwhich it may be locked in angular rotation. With these and other objectsin view, the invention consists of certain novel features ofconstructionVfas will Ibe `more-fully described and particularly pointed.out Vin the' appended claims'- .f 1 Y f In the accompanying drawings:yl

Fig. `1 is atop plan view ofthe iixture -with parts broken awayA formoreclearl'y viewing the inner working' parts.

Eig. 2 isa sectional view taken through the cam follower which iscarried by ythe reciprocating work carrier. f

Fig. 3` is a central sectional'` viewV on substantially line'3-3 of Fig.1.

Fig. 4 is a sectional view on substantia y-line 4-4 of Fig. 1. x

Fig. 5 is a `sectional view on substantially line 5'-50f Fg. 1. y 1

Figx isa top plan view illustrating certainv of the moving parts inorder .thatftheir operation may be better understood;

Fig. 7 is a top'plan view of. a fragmentallshowf ing of Fig. 2. I f Fig.ES is an elevationillustrating the complete fixture as mounted on afragmental showingof a table or othersupport and showing the-drive fromva tool arbor on which the tool is mounted, also illustrating in brokenline the workas pofsiftioned upon the xture.

In proceeding with this invention, I have progvideda frame in which all0f the moving parts are'contained, a pulley being: provided foroperation of the drive shaft from some arbor such as the tool arbor of amachine tool or other arbor upon which the tool which is'to operate uponthe Work is provided. AcamV shaft serves to provide the actuation of areciprocating carrier for-fthe work andalso serves'to'index the workwhen in a certain retracted position from" the-tool which operates uponthe work. A brake is provided. to hold the work While the pawl operatesto takea new grip, and locking means are provided for locking the workdefinitely in an indexed Yposition after it has been turned tofsuchposition. These lockingv means are automaticallyA withdrawnat the: timeof-index. Adjustments are vprovided so various` amounts. of--indexingare provided. The mechanism is such that it mayv be locked: in a largenumber of positions of indexing so .that very ne lwork may be done onthe machine.

With reference to the drawings, in designates a frame, whi'chmay berectangular, having ends H and l2 which are'connected to side walls Id,I5, allof which are provided with flanges I3 to be secured toa supportI6 vby some means such as' shoe I7 and bolt. A top wall 20 (see Fig. 4)is provided with slideways 2 l, undercut as at 22, 4for the reception ofa work carrier 23, which has an edge 24 to fit the slideway 22 on oneside, and is provided with an adjustable edge 25 to fit the slideway 2|on the other side. This work carrier has mounted upon it most of theoperating parts of the mechanism.

A main actuating shaft 26 extends laterally of the fixture and isrotatable in bearings and driven from a pulley 21, which, as shown inFig. 8, is driven by reason of belt 28. circling this pulley 21 and alsoengaging a driving pulley 29 on the arbor 30 which carries the workcutter or tool 3 I. This belt 28 is trained over an idler 32, alsomounted on the frame of this fixture. The main drive shaft 26 has a worm33 thereon (see Fig. l) which drives the worm gear 34, which in turndrives the worm and in turn drives the worm wheel- 36, as shown in Fig.5. The worm gear 36 is mounted on the cam shaft 31 which extendslaterally of the machine and carries cams 38 and 39 for performingcertain actuating functions.

The work carrier 23 has an arm 40 having a cam follower 4|, mounted inone end thereof, which is in a position to engage the cam 38. Thesprings 42 and 43' attached to the frame and engaging ends 44 and 45secured to the work carrier 23, urge the carrier toward the left asshown in Figs. 1, 3, and 6 so as to cause the cam follower 4| to engagethe cam 38. As the cam rotates, the work carrier will be moved to theright, as shown in Figs. l, 3, and 6, while the springs will return thecarrier, moving it; toward the left. Thus the reciprocating movement ofthe carrier is provided.

A vertically extending boss 45 (see Fig. 4) receives a bushing 46 inwhich there is rotatably mounted a mandrel 41 which is flanged withnotches therein and is reduced as at 48 and threaded. Different collarsfor mounting the work are screwed onto this reduced portion 48 andsuitably held in position. Collars of different diameters may beprovided for work of varying diameters.

The lower end of the mandrel 41 is reduced as at 56 (see Fig. 3) uponwhich there is mounted a ratchet wheel 5| (see Figs. 3, 4) and a gearWheel 52, and a second duplicate gear wheel 53. These gear wheels, 5|,52, and 53, are all locked to each other and to the mandrel 41 by a pin54 and also by a securing bolt which extends through all of them andfastens into the mandrel. The gears 52 and 53, although of duplicateconstruction, are so arranged that the teeth of the gear 52 will beopposite the recesses in the gear 53, and vice versa, as shown moreparticularly in Fig. 4.

A plate 56 is rockably mounted on that portion of the bushing 46 whichextends below the boss 45. This plate carries pawls 51 and 51', pivotedas at. 58, and urged inwardly by a spring 59 so as to engage the teethof the ratchet 5|. The pawls 51, 51' are of unequal length by one half atooth to enable more accurate adjustment. Plate 56 is connected by link66 to a lever 6 pivoted as at 62, and connected to the cam followerslide 63, which is slidably mounted in recess 54' (see Fig. 1) of thecarrier 23. This slide 63 has rotatably mounted on it a cam follower 64to be engaged by the cam 39. A spring 65, attached tothe link 60, rocksthe lever 8| counterclockwise as shown in Figs. 1 and 6, tending to movethe slides 83 to the left as shown in these figures. A slot 66 isprovided in this slide 63 and the cover 61 (see Figs. 2, 3, and 7) alsohas a slot 68 for slidably mounting a pin 69 therein in any adjustedposition by reason of the nut 16. This pin 69 will limit the movement ofthe slide 63 and thus limit the number of teeth that the pawls 51 or 51'will pick up when the plate 56 is moved counterclockwise as shown inFig. 6. It will be readily apparent that when the slide is moved to theright as shown in Figs. 1 and 6, by the cam 39 when it engages thefollower 64 the lever 6I will be rocked to move the plate 56 clockwise,and, by reason of the pawls, 51 or 51' engagingthe ratchet 5|, themandrel will b e rotated I in a l predetermined amount dependent uponthe adjustment of the pin 69.

The plate 56 carries an upstanding cam 12, having an actuating surface13 and cam surface 14 for engaging and urging inwardly the pin 15,which, through spring 16. presses a shoe 11 against the mandrel 41 toapply friction thereto. This cam 12 is attached to the plate 56 byscrews 18 extending through slots 19 so that the cam may be adjusted onthis plate. The surface 13 will engage the pin to apply maximum pressureto the mandrel as the pawls are moving counterclockwise to take a newgrip. The resiliency, however, will permit of positive movement of theratchet wheel by the pawl action justabove explained. In some cases, itmay not be necessary to have a brake such as heretofore described.

The work carrier 23 extends downwardly as at (see Fig. 3) for thereception of the lever 6| and below this downwardly extending portion,blocks 8| and 82 are provided, carrying locking fingers 83 and 84 whichare pressed by springs 85 and 86 to ca-use these fingers to enter one ofthe spaces between teeth of the gears with which they are aligned. Ifone gear is in registry with its locking finger, it will be apparentthat the other one is out of registry with its locking finger, and thusthis finger will engage one of the teeth instead of the space betweenthe teeth. In order to withdraw these locks 8| and 82 I have provided alever 81, pivoted as at 88, and located inthe path of movement of anabutment 89 (see Fig. l) mounted on the carriage or carrier 23. Thus, asthe carriage 23 moves toward the cam shaft, this block 89 will engagethe lever 81 and swing the lever about its pivot. The levers have theirother ends 98 entering recesses 9| in the blocks so as to withdraw theblocks from the gears, permitting indexing by the ratchet mechanismabove described.

It will be readily apparent that the reciprocation of the carrier 23upon which the. workis mounted takes place by reason of the rotation ofthe cam 38 and is unaffected in its action by any other mechanism of thefixture. It will also be apparent that the stroke of the carrier assistsin unlocking the work, but that the indexing is independent of themovement of the carrier by reason of the cam 39 engaging the slide whichactuates the pawl, causing the rotation of the work which is mounted onthe mandrel. A brake may or may not be necessary to retard the movementof the work during the return of the pawl for a new grip. The cover 61is mounted in a location which is readily accessible from the top of thefixture and, by adjustment of the nut 1|) to a position along thegraduations (see Fig. 7) on the cover, the angular rotation or amountoi' indexing may be readily adjusted.

By reason of a plurality of gears for locking the mandrel in place, Imaintain the strength of large teeth, which is desirable, and bystaggering the arrangement of the teeth and providing a plurality oflocking plungers I am able to obtain a very fine angular amount ofindexing, divided up into any desired number, which will be amultiplication of the teeth in any gear by the number of gears which areprovided. For instance, in the particular showing here, I might have 40teeth in each of the gears 52 and 53, and thus I would divide the 360degrees angular rotation into 80 spaces by having two duplicate gears of40 teeth each, and yet the strength of a LlO-tooth gear is provided. Inthe case of the pawl and ratchet mechanism, one large ratchet havingstrong teeth is provided and two pawls 51, 51 or any multiple of pawlsare provided, and these are so arranged as to divide the distancebetween the ratchet teeth into even divisions for dividing the angularrotation of the ratchet gear into increments less than the distancebetween teeth.

By changing the pitch of the worm mechanism, as for instance the pitchof the worm 33, I may vary the speed of the device. This worm may bemade readily interchangeable, or the size of the pulley 21 might bechanged to vary the speed throughout. It is readily apparent that theiixture is readily flexible for various speeds and functions and that itis extremely simple in its construction.

The xture may be mounted upon any support adjacent a cutting tool andparticularly may be mounted upon a machine tool, on the table thereofwhich will be maintained fixed, all movement being had by the xturewhich is mounted thereon.

I claim:

1. A fixture for a machine tool comprising a frame adapted to be securedto a suitable support, a work carrier slidably mounted on said frame, afirst cam means operable for reciprocating said carrier for feeding thework, and second cam means operable at the end of the return stroke ofsaid carrier for indexing the work while said carrier is withoutmovement.

2. A xture for a machine tool as set forth in claim 1 wherein means areprovided for locking the work in position after indexing.

3. A xture for a machine tool as set forth in claim 1 wherein saidindexing means comprise a pawl and ratchet.

4. A fixture for a machine tool as set forth in claim 1 wherein saidindexing means comprise a pawl and ratchet and actuating cam.

5. A fixture for a machine tool as set forth in claim 1 wherein saidindexing means comprise a pawl, ratchet, and cam follower, said followerbeing adjustable as to the stroke thereof.

6. A xture for a machine tool as set forth in claim 1 wherein saidindexing means comprise a pawl and ratchet and a brake to hold the workduring movement of the pawl.

7. A fixture for a machine tool as set forth in claim 1 wherein meansare provided for locking the work in position after indexing andcomprising a plurality of coaxial gears with their teeth out of registryand fingers to engage each of the gears for locking the same inposition.

8. A xture for a machine tool as set forth in claim 1 wherein means areprovided for locking the work in position after indexing and comprisinga plurality of coaxial gears xed on the Work shaft with their teeth outof registry and a plurality of ngers one for each gear, to engage eachof the gears for locking the same in position.

9. A xture for a machine tool as set forth in claim 1 wherein a brake isprovided to hold the Work during indexing.

10. A xture for a machine tool as set forth in claim l wherein means areprovided for locking the work in position after indexing, and a brake isprovided to hold the work during indexing.

11. A fixture for a machine tool as set forth in claim 1 wherein saidindexing means comprise a pawl and ratchet, and means to adjust themovement of the pawl.

12. A fixture for a machine tool comprising a frame adapted to bedetachably secured to a support, a work carrier slidably mounted on saidframe, a drive shaft having bearings in said frames, a cam shaft havingcams thereon driven by said drive shaft, a cam follower secured to apart attached to said carrier for engaging one of said cams to slidesaid carrier in one direction upon movement of said cam and resilientmeans to return said carrier for holding the follower in engagement withthe cam, a mandrel for mounting the work rotatably supported by saidcarrier, a ratchet secured to said mandrel, a pawl movable about saidmandrel for engaging said ratchet, a cam follower slidably mounted insaid carrier and engageable with another cam when the carrier is at oneend of its stroke for sliding said follower relative to said carrier andmeans responsive to said relative movement of said follower to actuatesaid pawl. means to adjustably limit the movement of said follower,whereby to adjust the throw of said pawl, means actuated by means tomove said pawl to apply a brake to said mandrel, a pair of gearspositioned coaxially with the teeth of one registering with the spacesbetween the teeth of the other, a pair of blocks fixed to said mandrel,each having fingers, one for each gear, to enter the spaces between saidgear teeth and lock the mandrel in place, and means responsive to themovement of said carrier toward said cam shaft to widthdraw said iingersfrom locking position.

EDWARD E. POW ZELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 607,629 Reece July 19, 1890936,915 Kustner Oct. 12, 1909 1,533,165 Cross Apr. 14, 1925 1,621,145Weber Mar. 15, 1927 1,827,965 Anthony Oct. 20, 1931 1,831,869 KesslerNov. 17, 1931 2,187,544 Saessher Jan. 16, 1940 2,261,052 Cofn et al Oct.28, 1941 2,359,601 Andrews et al Oct. 3, 1944

